Device for focussing and deflection of an electron beam in a cathode-ray apparatus

ABSTRACT

A device for focussing and deflecting an electron beam in a cathode-ray apparatus wherein at least two windings are disposed coaxially, the planes of the winding turns being symmetrically inclined at the same angles relative to the longitudinal axis of the windings. The two windings are connected to the output stage of a supply generator built around a transistor in a split-load circuit.

United States Patent Efimov et al.

[ 1 July 22,1975

i 1 DEVICE FOR FOCUSSING AND [58] Field of Search 315/27 XY, 27 TD, 382, DEFLECTION OF AN ELECTRON BEAM IN 315/403, 335/ A CATHODE-RAY APPARATUS 176] inventors: Ivan Ivanovich Efimov, ulitsa [56] References Clted Stroitelei 7, korpus 1, kv. 96, UNITED STATES PATENTS Moscow; Mikhail Lvovich Lifshits, 3,502,941 3/1970 Buechel 315/27 TD ulitsa Moskovskaya 3, kv. 18, 3,735,236 5/1973 Richter et al..... 315/27 TD Lobnya Moskovskoi oblasfl; 3,743,983 7/1973 Holman 335/213 X Dmitrievich Nikiforov, ulitsa g Sretenka, 26/1, kv. 2, Moscow; Wa Viktor Pavlovich lvanov, Putevoi 3,784,869 l/1974 Takahashi 315/27 TD prozed, 8, kv. 56, Moscow; Lev Efimovich Linetsky ulitsa Przrnary Examzr lerMaynard R. Wilbur Metrostmevskaya 13/12 kv l3 Asszstant ExammerG. E. Montone Moscow; vadim eorgie"lich' Attorney, Agent, or Firm-Holman & Stern Lazarev, ulitsa Norilskaya l, kv. 140, Moscow; Alexandr Ivanovich [57] ABSTRACT Brenin, prozed Cherskogo, 11, kv. A device for focussing and deflecting an electron 63, Moscow, all of USSR. bearn in a cath de-ray apparatiis whherein at least two 3 windings are isposed coaxial y, t e planes of the Filed" July 1973 winding turns being symmetrically inclined at the [21] A 1. No.: 379,391 same angles relative to the longitudinal axis of the windings. The two windings are connected to the out- I put stage of a supply generator built around a transis- [52] US. Cl. 315/403,ii'glsiglli 331383892 tor in a Split load circuit. [51 Int. Cl H01j 29/58; H01j 29/70 2 Claims, 3 Drawing Figures our/ ar y JUPPLY GENE/Z4701? l 3 POWER I [7 g/fl JOZ/ECE 171 l I r l r 75 L l I 15 i l l i l 4 i l I I t l i Q I? Z T l i Z l '1 l I L i L l SWAP/N6 STAGE 7 PATENTED L .896.339

v 5 J i A 7 1 DEVICE FOR FOCUSSING AND DEFLECTEON OF AN ELECTRON BEAM IN A CATI-IODE-RAY APPARATUS BACKGROUND OF THE INVENTION The invention relates to arrangements for magnetic control of an electron beam, more particularly, to a device for focussing and deflecting an electron beam in a cathode-ray apparatus.

There exist in the prior art devices for focussing and deflecting an electron beam in a cathode-ray apparatus which comprise windings.

In a prior art device for focussing and deflection an electron beam in a cathode-ray apparatus at least two windings mutually disposed so as to provide focussing and scanning of the electron beam on the operating surface of the cathode-ray apparatus are connected to the outputs of a supply generator which comprises shaping and output stages coupled to a power source.

A disadvantage of the existing device for focussing and deflecting an electron beam in a cathode-ray apparatus is the complexity of its design which is due to the fact that separate windings which have different construction and are connected to different stages of a supply generator have to be used for focussing and for deflecting the electron beam.

Another disadvantage of the existing device is that it is difficult to manufacture since special tools and formers for the deflection coil have to be fabricated and the winding of a deflection coil is rather a complicated process.

A further disadvantage of the existing device is that it has large dimensions and weight owing to its specific design features and to the use of separate stages of the supply generator for beam focussing and scanning.

Still another disadvantage of the existing device is that it is difficult to align because of the need for compensating the angular displacement of the raster on the operating surface of the cathode-ray apparatus which is caused by the separation of the focussing and deflection fields.

Furthermore the existing device is disadvantageous in that the resolution at the raster edges is poorer than in the center, which is also due to the separation of the focussing and deflection fields.

SUMMARY OF THE INVENTION The object of the invention is to provide a device for focussing and deflecting an electron beam in a cathoderay apparatus wherein the windings are so disposed so as to make the entire device easier to manufacture, to cut down its dimensions and weight and to improve resolution.

With this and other objects in view in a device for focussing and deflecting an electron beam in a cathoderay apparatus, at least two windings, a first winding and a second winding, mutually disposed so as to provide focussing and scanning of the electron beam on the operating surface of a cathode-ray apparatus are connected to the outputs of a supply generator comprising shaping and output stages and, according to the invention, the windings are disposed coaxially while the planes of the turns in each pair of the windings connected in series are inclined symmetrically and at the same angles relative to the axis of the windings, each output stage using transistor, the emitter and collector thereof being connected to the first leads of a first resistor and a second resistor, respectively, while the junction point of the pair of the windings is connected through a capacitor to the collector, a second lead of the second resistor is connected to a second lead of the first winding and through a parallel combination of a third resistor and a capacitor to a negative lead of a power source, the transistor base is connected through a series combination of a fourth resistor and a diode to a second lead of the second winding, the second lead being connected through a parallel combination of a fifth resistor and a capacitor to a positive lead of the power source to which a second lead of the first resistor is connected.

The device preferably comprises an additional winding disposed coaxially relative to the above-mentioned windings, the planes of the turns of the additional winding being normal to the axis of the windings.

The device for focussing and deflection of an electron beam in a cathode-ray apparatus can be used in small-size television cameras where high performance has to be obtained with small dimensions and weight.

BRIEF DESCRIPTION OF THE DRAWING Other objects and advantages of the invention will be apparent from the following description of its specific embodiments when read in connection with the accompanying drawings in which:

FIG. 1 is a block diagram of a device for focussing and deflection of an electron beam of a cathode-ray apparatus, according to the invention, with a sectional view of the cathode-ray apparatus;

FIG. 2 is a schematic diagram of the output stage of a supply generator showing the connection of the generator with other units of the device for focussing and deflection of an electron beam according to the invention;

FIG. 3 is a block diagram of a device for focussing and deflection of an electron beam in a cathode-ray apparatus, including an additional winding, according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS A cathode-ray apparatus 1 (FIG. 1) in the form of a vidicon has an operating surface 2 and an electron gun 3. Windings 4 and 5 are disposed coaxially relative to an axis 6 and are wound one on top the other. The planes of the turns in each winding 4 and 5 are symmetrically inclined at the same angles a relative to the axis 6. The windings 4 and 5 are connected in series and are coupled to an output stage 7 of a supply generator 8 which includes a power source 9 and a shaping stage 10. The power source 9 is connected to the output stage 7 and to the shaping stage 10.

The output stage 7 shown in FIG. 2 uses a transistor 11, the emitter and the collector thereof being connected to first leads of resistors 12 and 13, respectively. A junction point 14 of the windings 4 and S is connected to the collector of the transistor 11 through a capacitor 15 while a second lead of the resistor 13 is connected to a second lead of the winding 4 and through a parallel combination of a resistor 16 and capacitor 17 to a negative lead of the power source 9. The base of transistor 1 l is connected through a series combination of a resistor 18 and a diode 19 to a second lead of the winding 5, which is coupled through a parallel combination of a resistor 20 and a capacitor 21 to a positive lead of the power source 9, to which a second lead of the resistor 12 is also connected.

FIG. 3 shows a block diagram of the device for focussing and deflecting an electron beam in a cathode-ray apparatus including an additional winding 22 disposed between the windings 4 and 5.

The planes of the turns in the winding 22 are normal to the axis 6 and the winding 22 is connected directly to the power source 9.

The device for focussing and deflecting an electron beam in a cathode-ray apparatus described herein operates as follows.

When the power source 9 is connected, the shaping stage 10 furnishes control signals in the form of a sawtooth voltage at the scanning frequency. These signals are applied to the base of the transistor 11 and unbalance a bridge network formed by the windings 4 and 5, the resistors 12 and 13 and the transistor 11, causing equal and opposite currents to appear in the windings 4 and 5. A constant DC. current flows through the resistor 16, the windings 4 and 5 and the resistor 20. Changes of this current vary the voltage drop across the resistor and the changing voltage is applied through the diode l9 and the resistor 18 to the base of the tran sistor ll changing the DC. component of the current through the transistor 11, which eventually stabilizes the DC. current flowing through the windings 4 and 5. Thus the increase of the current through the windings 4 and 5 causes a greater voltage drop to be produced across the resistor 20 with the result that a higher current flows through the transistor 11. This increases the voltage drop across the resistor 16 and decreases the DC. current flowing through the windings 4 and 5.

The stabilized DC. current flowing through the windings 4 and 5 sets up a magnetic field which focusses the electron beam on the operating surface 2 (FIG. 1) of the cathode-ray apparatus 1.

The equal and opposite currents flowing in the windings 4 and 5 change the direction of the magnetic field set up by the DC. current. As a result, the focussed electron beam scans the operating surface of the cathode-ray apparatus in one plane. To cause the electron beam to scan in the second plane use must be made of two more windings with the associated shaping and output stages (not shown), the windings being oriented in accordance with the desired plane of scanning.

When the additional winding 22 is used the DC. cur rent flowing through this winding produces an additional focussing magnetic field which adds to the main focussing field set up by the windings 4 and 5. By changing the current through the winding 22 a better match is obtained between the windings 4 and 5 and the output stage 7 of the supply generator 8.

The device for focussing and deflecting an electron beam in a cathode-ray apparatus may be used where a high quality of display, simple construction, low cost and small weight are important.

The advantages of the device of the instant invention make the device most suitable for use in small-size field television cameras furnished with video tape recorders and in applied television in television cameras for inspection of small-diameter tubes.

The device described herein owes its unquestionable superiority to its small size, simple construction and convenience of manufacture.

What is claimed is:

l. A device for focussing and deflecting an electron beam in a cathode-ray apparatus which comprises two windings disposed coaxially in operative relationship with the apparatus to provide focussing and scanning of the electron beam on the operating surface thereof, said device comprising: supply generator means for producing stabilized direct current for focussing said electron beam and alternating current for deflecting said electron beam. said supply generator means having an operatively interconnected shaping stage and output stage, the input to said output stage being coupled to the output of said shaping stage; and a power source for supplying power to the device which includes a negative lead and a positive lead and is operatively coupled with said shaping and output stages; a pair of windings operatively coupled to said output stage, said pair comprising a first winding and a second winding each having a first lead and a second lead and being connected in series by means of said first leads, the two planes defined by the two sets of turns of the windings of said pair of windings being mutually non-parallel, said planes inclined at equal angles relative to the co-axis of said windings; a transistor of said output stage, said transistor having a collector, an emitter and a base; a first resistor of said output stage which has a first lead and a second lead and is connected to said emitter by means of the first lead thereof; a second resistor of said output stage said second resistor having a first lead and a second lead and connected to said collector by means of the first lead thereof; a first capacitor of said output stage, one lead of said capacitor being connected to said collector, the other lead, to a junction point defining the connection of the windings of said pair of windings, the second lead of said second resistor being connected to the second lead of said first winding; a third resistor of said output stage, a first lead of said third resistor being connected to the second lead of said second resistor, and a second lead of said third transistor, to the negative lead of said power source; a second capacitor connected in parallel with said third resistor; a fourth resistor of said output stage which has a first lead and a second lead and is connected to said base by means of the first lead thereof; a diode of said output stage, a first lead of said diode being connected to the second lead of said fourth resistor, the other lead of said diode being connected to the second lead of said second winding; a fifth resistor of said output stage, a first lead of said fifth resistor being connected to the second lead of said second winding, and a second lead thereof, to the positive lead of said power source; a third capacitor of said output stage connected in parallel with said fifth resistor the second lead of said first resistor being connected to the positive lead of said power source.

2. A device as claimed in claim 1 comprising at least one additional winding disposed coaxially relative to said windings and connected to said power source, the planes of the turns of said additional winding being normal to the axis of said windings. 

1. A device for focussing and deflecting an electron beam in a cathode-ray apparatus which comprises two windings disposed coaxially in operative relationship with the apparatus to provide focussing and scanning of the electron beam on the operating surface thereof, said device comprising: supply generator means for producing stabilized direct current for focussing said electron beam and alternating current for deflecting said electron beam, said supply generator means having an operatively interconnected shaping stage and output stage, the input to said output stage being coupled to the output of said shaping stage; and a power source for supplying power to the device which Includes a negative lead and a positive lead and is operatively coupled with said shaping and output stages; a pair of windings operatively coupled to said output stage, said pair comprising a first winding and a second winding each having a first lead and a second lead and being connected in series by means of said first leads, the two planes defined by the two sets of turns of the windings of said pair of windings being mutually non-parallel, said planes inclined at equal angles relative to the co-axis of said windings; a transistor of said output stage, said transistor having a collector, an emitter and a base; a first resistor of said output stage which has a first lead and a second lead and is connected to said emitter by means of the first lead thereof; a second resistor of said output stage said second resistor having a first lead and a second lead and connected to said collector by means of the first lead thereof; a first capacitor of said output stage, one lead of said capacitor being connected to said collector, the other lead, to a junction point defining the connection of the windings of said pair of windings, the second lead of said second resistor being connected to the second lead of said first winding; a third resistor of said output stage, a first lead of said third resistor being connected to the second lead of said second resistor, and a second lead of said third transistor, to the negative lead of said power source; a second capacitor connected in parallel with said third resistor; a fourth resistor of said output stage which has a first lead and a second lead and is connected to said base by means of the first lead thereof; a diode of said output stage, a first lead of said diode being connected to the second lead of said fourth resistor, the other lead of said diode being connected to the second lead of said second winding; a fifth resistor of said output stage, a first lead of said fifth resistor being connected to the second lead of said second winding, and a second lead thereof, to the positive lead of said power source; a third capacitor of said output stage connected in parallel with said fifth resistor the second lead of said first resistor being connected to the positive lead of said power source.
 2. A device as claimed in claim 1 comprising at least one additional winding disposed coaxially relative to said windings and connected to said power source, the planes of the turns of said additional winding being normal to the axis of said windings. 